1. Field of the Invention
The present invention relates to a dental anesthetic injection device, and more particularly, to a dental anesthetic injection device capable of controlling an anesthetic jet pattern.
2. Discussion of Related Art
Generally, as a method of parenterally injecting a therapeutic agent into a body of a patient, various drug delivery systems have been applied. Among such drug delivery systems, the most generally used method is to use syringes with a needle, in which a medication is directly injected beneath the skin using a syringe with an injection needle. However, dental anesthetic is injected into a particular skin different from general skin, such as oral mucosa, gingival sulcus, a pulp cavity, etc. That is, oral mucosa is covered with moist mucous membranes formed of protein such as mucin, etc. and a thin keratinous layer, gingival sulcus is a micro pocket-shaped structure having an area of several hundred micrometers in direct contact with scleroid teeth and constantly filled with an exudation and saliva, and a pulp cavity is a structure formed of soft tissue in teeth surrounded by hard enamel, an inside of which is a complex of blood vessels, nerves, and fibrous tissues and filled with lymph fluid and an exudation.
To an oral structure having an environment of such a particular structure, it is general to deliver anesthetic through a syringe. Accordingly, pain should necessarily occur, and it is necessary to develop an anesthetic delivery system capable of relieving such pain.
General microjet drug delivery apparatuses use a principal in which a liquid is injected from an end of a nozzle at a high speed and penetrates soft material such as the skin of a human being to deliver a liquid thereinto, which is effective when a surface is dry. However, general microjet drug delivery apparatuses deteriorate in penetrating power due to a liquid present on a surface of a pulp cavity formed of multiple tissues with irregular density, a surface of oral mucosa or an inside thereof which is already filled with another liquid. Since a drug is injected toward multiple tissues at a certain speed, weak tissues may be destroyed. Accordingly, it is impossible to effectively deliver dental anesthetic using conventional microjet drug delivery apparatuses and development for this is necessary.